Safety seat belt buckle



July 23, 1968 E. BARCUS 3,393,433-

SAFETY SEAT BELT BUCKLE Filed. July 18, 1967 2 Sheets-Sheet 1 INVENTOE[aw/420 A 542m ATTORNEYfi July 23, 1968 I cus 3,393,433

SAFETY SEAT BELT BUCKLE 2 Sheets-Sheet 2 Filed July 18, 1967 UnitedStates Patent 3,393,433 SAFETY SEAT BELT BUCKLE Edward L. Barcus,Flossmoor, IlL, assignor to Pontonier, Inc., Chicago, Ill., acorporation of Illinois Filed July 18, 1967, Ser. No. 654,180 12 Claims.(Cl. 24-430) ABSTRACT OF THE DISCLOSURE A safety belt buckle has a baseto which one end of a belt may be attached and a tongue plate forattachment to another end of the belt. A spring biased latch member ispivotally mounted on a base to move a latch dog thereon between arelease position in which the tongue plate can be retracted from thebase, and a latching position in which the latch dog projects into anopening in the tongue plate and engages an abutment wall defining aportion of the opening. To assure latching, the latch dog is formed witha sinuously shaped leading wall with bends in one direction extendingbeyond one face of the tongue plate and a bend in the opposite directionextending beyond the opposite face of the tongue plate. Preferably, thesinuously shaped leading wall is sloped and abuts an edge of saidabutment Wall at three spaced regions. The base may be provided with acovered slot to receive the lower edges of the first mentioned bendswhen the latch dog is in the latching position.

This invention relates to a safety belt buckle, and more particularly toa safety belt buckle adapted for releasably fastening together the endsof straps, belts and the like.

In safety belt buckles, a tongue plate having an opening or recess isattached to one end of a belt and is latched to a base of the buckle bya latch dog carried on a pivotally mounted latch member. In someinstances, a pair of spaced openings are provided in the tongue platefor receiving a pair of spaced dogs carried on the latch member. Inother buckles, a single wide dog may be projected into a single, largeaperture in a tongue plate. If the upper edge of the dog has a long,straight line of contact with the wall defining the latch opening,repeated and considerable usage of the buckle may cause a groove ornotch to form in this wall. Then, when the belts attached to the buckleand tongue plate are under tension, the dog may become embedded in thisgroove and the dog will be held against release with the usual amount ofpull on the cover lever. For example, after exertion of a tension forceof 2,500 lbs. on the buckle and tongue plate belts, the dog may beembedded to the extent that it will not release with operation of a pushbutton or with a 30 lb. pull on a cover lever, even after the load isreduced to 150 lbs., and thus fail to meet certain safety standards.

Advantageously, the latch dog should project into the latch opening andhave surfaces disposed above and beneath the upper edge of the openingto assure that a positive latching occurs. Also, it is preferred thatthe dog and tongue plate be related to reduce the prospect of rattlingof one on the other.

Accordingly, a general object of the invention is to provide a new andimproved seat belt buckle in which the latch dog is inserted for aconsiderable depth into the latch opening to assure a positive latching,yet which freely releases.

A further object of the invention is to achieve the foregoing object bya sinuously shaped latch dog having a sloped surface for abutting anedge of a wall defining the latch opening.

A further object of the invention is to provide a seat buckle which hasa latch dog fully projecting into the latch opening and yet has a smoothunderside for sliding across the wearers apparel.

Other objects and advantages of the invention will be apparent from thefollowing description taken in connection with the accompanying drawingsin which:

FIGURE 1 is a perspective view of a safety belt buckle constructed inaccordance with and embodying the novel features of the presentinvention;

FIGURE 2 is an enlarged perspective view of the buckle of FIGURE 1 withthe cover raised to an open release position;

FIGURE 3 is a perspective view of the latch member of the buckle shownin FIGURES 1 and 2;

FIGURE 4 is a longitudinal sectional view taken substantially along theline 4-4 of FIGURE 5;

FIGURE 5 is a sectional view taken substantially along line 55 of FIGURE4;

FIGURE 6 is an enlarged, fragmentary, longitudinal, sectional view ofthe latch dog disposed in its latched position; and

FIGURE 7 is a fragmentary, sectional View taken along line 7-7 of FIGURE5.

As shown in the drawings for purposes of illustration, the invention -isembodied in a safety belt buckle 10, in which very generally, the buckleis attached to one end 11 of a belt and a removable tongue plate 12 isfastened to another end 13 of the belt. To fasten these belt endstogether, the tongue plate 12 is inserted in a slot between a cover 14and a base 15 and then projected longitudinally along the base of thebuckle to aligne a latch opening 16 (FIGURE 4) in the tongue plate withsinuously-shaped latch dog 17 carried on a latch member 19. The latteris biased by a torsion spring 20 (FIGURE 2) to project the latch doginto the latch opening 16 to the extent that the lower edges of thelatch dog extend into a groove 18 (FIG- URE 2) in the bottom of buckle,and surfaces 23 on the dog abut a forward wall 21 defining a portion ofthe latch opening.

To move the latch member 19 to a release position, in which the latchdog is spaced above the latch opening, the illustrated buckle has itscover 14 in the form of a lever with a free end 22 adapted to be graspedand pivoted upwardly from the base to the position of FIGURE 2 againstthe biasing force of the spring 20. A rear portion 24 (FIG- URE 4) onthe cover plate includes a pair of shoulders abutting the rear edge ofthe latch member 19 to pivot the latter to raise the latch dog to therelease position shown in FIGURE 2.

In accordance with the invention, a positive latching is provided by asinuously-shaped dog 17 abutting the tongue plate 12. Spaced contactareas 23 abut an upper edge of the abutment wall 21 in the tongue plateand provide a good, full, positive latching while a sloped surface 25 ona leading wall of the latch dog is unlikely to form an embedding groovewhich will hold the dog against release movement, as will be explainedin detail hereinafter. Another feature of the invention, which will bedescribed in detail, is providing shoulders on the latch member to holdthe tongue plate against the bottom wall of the buckle for the purposesof assuring a predetermined relationship between the sinuously-shapedleading wall and the tongue plate and also preventing rattling of tongueplate.

Proceeding now with a more detailed description of the individualelements, the buckle base 15 is, in this instance, in the form of achannel with a pair of upstanding flanges 26 and 28 (FIGURE 2) extendinglongitudinally along and generally perpendicularly to a central baseplate 29 disposed between the flanges. At one end of the channel base, abelt opening 30 (FIGURE 4) is formed in the base plate and extendstransversely across the base plate to the upstanding flanges 26 and 28.A portion of the base plate 29 is bent upwardly at an acute angle at thebelt opening of the central plate to form an upstanding lip 31. inwardlydirected tabs 32 are struck inwardly toward one another from the opposedside flanges 26 and 28 to form stops abutting the forward, generallyvertical wall of the lip 31 for the purpose of holding the lip againstbending forwardly, i.e., in a direction toward the free end 22 of thecover lever 14.

To clamp the end 11 of the belt to the base 15, a transverse knurled rod34 is disposed above the belt opening and between the side flanges 26and 28 for frictionally clamping the belt against the rear, generallyvertical wall of inclined lip 31. The opposite ends 35 (FIGURE 2) of therod 34 are flattened and are mounted for free sliding movement inelongated slots 36 formed in the flanges at the location of the beltopening. The slots are inclined downwardly and forwardly so that, whenthe leading end of the belt is inserted through the opening and trainedover the rod, the free end of the belt is nipped in the space betweenthe knurled rod and the lip. Exertion of a tension force on the beltpulls the rod toward the lip and tightens the grip on the belt. When itis desired to adjust the belt size, the tension in the belt is released,and the rod 34 is moved rearwardly and upwardly in the slots, whereuponthe belt can be slid about the rod to its adjusted position.

The cover lever 14 serves as a cover for the buckle and as a releaselever to unlatch the dog 17 from the tongue plate 12 when the cover ispivoted to the open position (FIGURE 2). Herein, the cover lever 14 isin the form of a channel with a central, fiat base plate 38 (FIGURE 2)disposed horizontally. A pair of longitudinally extending andtransversely spaced side flanges 39 and 4t) depend from the plate 38 andextend adjacent to and overlap the side flanges 26 and 28 of the bucklebase 15 when the cover lever is closed (FIGURE 1). In this closedposition, the inner, horizontal wall on the cover plate 38 abuts theupper longitudinal edges of the base flanges 26 and 28. At its rearwardend of the cover, the portion 24 is arcuately curved downwardly towardthe base 15.

To piovtally mount the cover lever 14 on the buckle base 15, a pivot pin41 extends transversely of and projects through aligned openings 42(FIGURE 5) in each of the side flanges 26, 28, 39 and 40. The pivot pin41 is disposed generally parallel to the buckle base plate 29 betweenthe overhead cover and the lower buckle base. The pivot pin is formedwith an integral, upset head 44 at one end and with an elongated slot 45at the other end of the pin. A releasable cover cap 46 is force fittedinto the slotted end of the pivot pin to hold the latter against axialmovement from the openings 42. The coiled torsion spring 20 encirclesthe pivot pin and has one end fitted into the elongated slot 45. ltsother end 49 extends radially from the pivot pin to engage the upperside of the latch member 19 to bias the latter to its latching position,as illustrated in FIGURE 4. The torsion spring 20 is woundup on the pinby partially inserting the pin into the cover 14 and using a driving key(not shown) which is inserted through the opening 42 in the side flangesand 28 and into the slot 45, to rotate the pivot pin about itslongitudinal axis. After winding, the pivot pin 41 is slid axially(FIGURE 5) to bring the open side of the elongated slot into alignmentwith an inward projection 52 formed in the wall at the opening 42 in theflange 40. The projection 52 seats in the slot 45 and holds the pivotpin against rotating and unwinding the torsion spring. Rather thanhaving the slot 45 extend entirely across the width of the pin, thepivot pin is strengthened by providing an outer wall 54 on the pindiametrically opposite the slot 45.

The latch member 19 for latching the tongue plate 12 is a generallychannel-shaped member (FIGURE 3) having transversely spaced flangesserving as trunnion arms 55 with aligned apertures 56 for journaling thelatch member on the pivot pin 41. The trunnion arms are disposedadjacent the side flanges 26 and 28 of the base and have terminalabutments 58 which extend radially and upwardly about the pivot pin 41and into rectangular slots in the portion 24 of the cover 14, to abutthe cover at the shoulders formed by the upper, transverse edges 60(FIG. 7) of the slots. The radially directed end 49 of the torsionspring 20 biases the abutments 58 against these edges 60 of the cover tourge the cover lever 14 to its closed position with its flanges disposedto substantially, fully overlap the flanges of the base.

In accordance with the present invention, the sloped surface 25 onsinuously shaped leading wall 61 of the latch dog 17 is abutted againstan upper edge 62 (FIGS. 4 and 6) of the abutment wall 21 when the latchdog is in its latching position. The dogs leading wall 61 is formed witha pair of downwardly extending bends 63 disposed on opposite sides of acentral upwardly extending bend 64. These bends are formed by a punchpress operation which deforms the front, central portion of a generallyflat horizontal plate 65 disposed between the side flanges 55 on thelatch member.

When the latch dog 17 is in its latching position, the undersurface ofthe plate 65 forms a pair of spaced shoulder surfaces 66 on oppositesides of the sinuously shaped latch dog. These shoulder surfaces 66 arebiased against and engage the upper face of the tongue plate 12. Toassure latching, the downward bends 63 are formed with sufficient depthto project through the opening 16 in the tongue plate and to inserttheir lower arcuate edges 67 at least partially in the groove 18 in thecentral plate 29 of the base; and the upwardly extending bend 64projects its upper arcuate edge above the upper face of tongue plate 12.The abutting edge 62 of the tongue plate wall 21 engages the latch dogat contact areas 23 which are in a generally horizontal plane defined bythe shoulder surfaces 66 on the underside of the latch member.

To prevent the abutment edge 62 on the tongue plate from embedding inthe latch dog, the leading wall 61 of the latch dog is sloped downwardlyat the surface 25 to slide along the edge 62 upon pivoting of the latchmember to the release position. More specifically, the sloped surface 25is formed to extend downwardly and away from the abutment wall so thatthe lower portion of the latch dog may swing upwardly past the abutmentedge 62 without undue interference. Furthermore, the dog is preferablyheat treated, making it harder than the tongue so that the tongue doesnot embed in the dog. Preferably the sloped surface 25 is formed by acoining operation during the formation of the sinuously shaped latchdog. The upper edge of the sloped surface constitutes the contact areas23 and the sloped surface extends downwardly and rearwardly therefrom.The sloped surface could be formed by other methods such as by grinding.The angle of inclination or slope of the surface 25 to the vertical isquite small so that the abutting edge 62 will not cam the latch dogupwardly to its release position but rather will firmly abut and give agood latching engagement. The surface 25 is sloped such that during therelease movement of the dog it slides substantially tangentially acrossthe abutment edge 62 as the latch member pivots upwardly about the axisof the pivot pin 41.

The upwardly extending bend 64 has its upper edge extending considerablyabove the horizontal plane of the shoulder surfaces 66 and hence, inlatching, it extends above the top of the tongue plate. At the same timethe lower edge of this upwardly extending bend projects into the latchopening 16 so that the upper rim wall of the latch opening at theabutment wall 21 may abut the bend 64 intermediate its upper and loweredges at the area 23. When the tongue plate engages the bend 63, thelatch dog engages the tongue plate at three widely spaced areas. Theforces are thus distributed along a plane at the underside of thecentral plate of the latch member so that there is no concentration offorces as would cause the buckle to fail.

It will be recalled that the groove 18 admits the lower edges 67 of thedownward bends 63 so that the shoulder surfaces 66 may engage the uppersurface of the tongue plate 12. Because the torsion spring 20 biases thelatch member 19, counterclockwise as viewed in FIGURES 2 and 4, theshoulder surface 66 may engage the upper surface of the tongue plate 12on opposite sides of the latch opening 16 and bias the tongue plate 12against the lower plate 29 of the buckle. The holding of the tongueplate 12 against the plate 29 prevents undesirable rattling of thetongue plate and assures positive latching.

In accordance with a feature of the preferred embodiment of theinvention the groove 18 does not extend through the base plate 29, andhence it covers the lower edge of the latch dog 17 while leavingtheunderside of the base plate 29 smooth and unapertured at the location ofthe dogs. The buckle base is therefore free to slide over the wearer.

The tongue plate 12 may take different forms but herein is in the formof a flat plate with upstanding short side flanges 68 and 69 (FIGURE 1)on opposite sides of a transverse opening 70 for receiving the end 13 ofthe belt which is doubled back and sewed to itself rearwardly of thetongue plate. From the side flanges, the tongue plate tapers inwardly toa forward end 71 to permit easy insertion while guiding the tongue tothe proper latching position.

To latch the tongue plate 19 to the buckle, the end 71 of the tongueplate is inserted in the slot 73 (FIG- UR-E 4) between the rear end ofthe latch member and the plate 29. When the end 71 strikes theundersurfaces of the bends 63 of the dog 17, it cams the latch member 19up to pivot it away from the base plate 29. The cover lever 14 remainsclosed as the shoulders 58 on the latch member 19 merely separate fromthe shoulders on the cover lever 14 at the upper ends of the coverlever. The lower forward edges 17 of the dog sli-de along the top of thetongue plate until the latch opening 16 is registered with the dog 17,whereupon the torsion spring 29 snaps the dog 17 into the latch opening16 and downwardly extending bends 63 project through the latch opening21 and into the groove 18. At the same time the central upward bend isarranged so that the leading wall extends centrally both above and belowthe upper edge of the abutment wall 21 in the tongue plate and therebyassures an abutment during periods of high stress or flexure of theparts, and also if there be some misalignment due to toleranceaccumulations. The tongue plate remains latched by the latch member 19until the cover lever 14 is pulled upwardly from the latch opening, atwhich time, the tongue plate is free for retraction from the slot 73.

From the foregoing, it will be seen that the seat buckle is constructedwith unique latch member having a latch dog for fitting into a singlelatch opening and shaped to prevent the embedding of the latch member inthe tongue plate. By providing spaced areas of contact between the latchdog and the tongue plate rather than a straight edge contact and byforming arcuate\or tapering surfaces on the latch dog, the latch memberreadily releases with a nominal amount of pull on the cover leverthereof, though the belts may be subjected to a substantial tensionforce.

While a preferred embodiment has been shown in the drawings anddescribed herein, it is not intended to limit the invention by suchdisclosure but, rather, it is intended to cover all modifications andalternative constructions coming within the spirit and scope of theinvention as defined in the appended claims.

It is claimed that:

1. In a safety belt buckle, the combination comprising a channel shapedbase having a central plate and a pair of spaced, upstanding flangesextending longitudinally along the opposite edges of said central plate,a channel shaped cover lever having a pair of longitudinally extendingflanges extending adjacent and parallel to said side flanges of saidbase, a pivot pin spanning both pairs of flanges at one end of the baseand mounting the cover lever on the base for pivotal movement betweenopen and closed positions, a latch member pivotally mounted on the pivotpin, a tongue plate insertable between said latch member and said baseand slidable longitudinally along said base, means including an abutmentwall defining a single latch opening in said tongue plate, a latch dogon said latch member having a sinuously shaped leading wall with atleast two downwardly extending bends on opposite sides of an upwardlyextending bend, said latch member being movable between a releaseposition in which said tongue plate can be retracted from said base anda latching position in which said downwardly extending bends projectinto said latching opening and the top of said upwardly extending bendprojects above the top of said abutment wall, said sinuously shapedleading wall abutting said abutment wall at spaced locations in saidlatching position thereby latching the tongue plate to the base, meansbiasing said latch member to its latching position, means on said latchmember for normally engaging said cover lever and urging said coverlever to its closed position, said latch member being disengaged fromsaid cover lever upon said latch member being moved against said biasingmeans by said tongue plate upon insertion thereof, thereby permittingsaid latch member to move to admit said tongue plate While said coverplate remains in its closed position.

2. The combination of claim 1 in which said central plate has atransverse groove for receiving the lower edge of said downwardlyextending bends and in which surfaces on said latch member engage andhold said tongue plate against said central plate.

3. The combination of claim 1 in which said leading wall on said latchdog has its lower portion beveled downwardly and rearwardly tofacilitate pivoting of the latch dog past said abutment wall uponmovement of the latch member to its release position.

4. In a safety belt buckle, the combination comprising a channel shapedbase having a central plate and a pair of longitudinally extending sidewalls extending along the opposite edges of the central plate, anelongated channel shaped cover lever having a pair of opposite sidewalls extending adjacent and parallel to said side walls on the channelbase, and a pivot pin spanning one end of the channels and mounting thecover on said base for pivotal movement between open and closedpositions, a tongue plate movable longitudinally relative to said base,a latch member pivotally mounted on said pivot pin and having anabutment wall at a single latch opening therethrough, a latch dogcarried on said latch member, which is movable between a releaseposition allowing retraction of said tongue plate from said base and alatching position in which said tongue plate is held against removalfrom said base, means biasing said latch member to its latching positionand acting through the latter to bias said cover lever to its closedposition, said latch dog having a leading wall With at least twodownwardly extending bends spaced on opposite sides of an upwardlyextending bend, a transverse groove in said central plate, the loweredge of said downwardly extending bends projecting into said groove whensaid latch member is in its latching position, and the upper edge ofsaid upwardly extending bend disposed above said tongue plate and itslower edge projecting into said elongated opening in said tongue platewhen said latch member is in its latching position, said leading wallabutting said abutment wall when said latch member is in its latchingposition. I

5. The combination of claim 4 in which said central plate is smooth anduninterrupted by said groove on the side adjacent the wearer of thebuckle.

6. The combination of claim 4 in which said bends engage said tongueplate at at least three spaced areas of contact along the upper rim ofsaid abutment wall.

7. The combination of claim 5 in which shoulders on said latch memberabut the top of said tongue plate in said latching position and urge thelatter against the central plate.

8. The combination of claim 7 in which said shoulders and said abutmentareas on said bends are in a horizontal plane at the upper surface ofsaid tongue plate.

9. The combination of claim 8 in which the portions of said bendsdisposed beneath said horizontal plane are sloped downwardly and awayfrom said abutment wall thereby facilitating the swinging of the bendsupwardly past the abutment wall upon movement of said latch dog to itsrelease position.

10. In a safety belt buckle, a base for attachment to one end of a belt,a cover carried by said base, a tongue plate for attachment to anotherend of a belt and insertable between said cover and base plate, saidtongue plate having opposite faces and an abutment wall defining oneside of a latch opening in the tongue, a spring biased latch memberpivotally mounted on said base, a latch dog on said latch member havinga sinuously shaped leading wall with oppositely extending bends, saidlatch member being movable between a release position in which saidtongue plate can be retracted from said base and a latching position inwhich at least one bend extending in a first direction projects throughsaid latch opening and beyond one face of the tongue plate and in whichat least one bend extending in the other direction projects beyond theother face of the tongue plate, said leading wall abutting said abutmentwall when said latch dog is in its latching position to said base.

11. A safety belt buckle in accordance with claim 10 in which a slopedsurface is formed on the sinuously shaped leading wall of said latch dogand abuts an edge of said abutment wall.

12. A safety buckle in accordance with claim 11 in which shoulders onsaid latch member abut a face of said tongue plate when the latter islatched to the base, and in which said sinuously shaped leading wallabuts said edge of said abutment wall in at least three spaced areas ofcontact.

References Cited UNITED STATES PATENTS 2,864,145 12/ 1958 Elsner 24-752,964,815 12/1960 Sereno. 3,241,206 3/ 1966 Greenfield.

BERNARD A. GELAK, Primary Examiner.

